The present invention, in some embodiments thereof, relates to expandable tissue dissecting devices, and, more particularly but not exclusively, to directionally controllable inflatable, optionally implantable, bladders configured for tissue dissection.
Dissecting and/or separating tissue layers are common techniques for placing implants and/or surgical devices inside a patient's body, as well as for removing unwanted tissues and organs. One such technique is commonly performed during surgical intervention for organ support, such as, for example, for mid-urethral support and/or prolapse prevention, where a mesh or other implant type is introduced for treating and/or preventing prolapse.
Dissection is also used for safely deploying medical devices and/or implants for protecting and/or treating tissue, for example during radiation therapy. Removal or treatment of pathological tissue such as cancer or malignant or benign growth or tumor caused by abnormal or uncontrolled cell division can be effected in any one of several well known approaches. A common form of treatment is surgery, followed by radiation (external or internal), chemical and thermal therapies. Examples of radiation therapies include but are not limited to external radiation beam therapy and interstitial brachytherapy, a technique in which radioactive sources are placed into a body, for example into the prostate gland, delivering radiation from within the prostate.
Prostate cancer is a common malignancy in men worldwide, with about 220,000 new cases diagnosed each year in the US alone. Each year, about 50,000 US patients undergo radical prostatectomy, in which all or part of the prostate gland is surgically removed. Over the last few years there is an increasing trend to use minimally invasive techniques such as laparoscopic radical prostatectomy (LRP).
Radical prostatectomy represents a delicate operation with a long learning curve, especially when are performed laparoscopically or by robotic surgery, where the learning curve may consist of 50 to 200 cases. One of the most challenging phases of the operation is a dissection and/or separation of the prostate from the rectal wall, where in laparoscopy or robotic surgery the practitioner's tactile sense is not effective.
Erectile nerves pass laterally to the prostate in close proximity to the superior and lateral vascular pedicles of the prostate. In order to preserve these nerves, the vascular supply to the prostate has to be sectioned close to the lateral margins of the prostate.
The prostate and surrounding tissues, as well as the space between rectum and prostate, may be visualized under high resolution using such modalities such as Trans-Rectal UltraSound (TRUS), MRI or CT. Additionally, urologists, interventional radiologists, and oncologists performing brachytherapy, are well accustomed to performing prostate biopsies and insertion of brachytherapy seeds through the perineum under TRUS guidance.
Separation of the prostate from the rectum is also performed during treatment of the prostate by other modalities such as ionizing radiation (external beam radiation or brachytherapy), thermal ablation, cryoablation, chemical ablation, electroporation, biological therapy with immunologic cell or vaccines, etc. These approaches can be practiced individually or in combination as adjuvant therapy.
In any case, the treatment procedure carries some degree of risk of injury to healthy tissues. For example, during surgery, use of surgical instruments in small, tight spaces can lead to inadvertent tissue injury. Radiation therapy or localized release of chemical substances can result in an intensity gradient between treated tissue and healthy tissue, and radiation or chemical injury to healthy tissues. As a result, a total energy or chemical dose for local treatment which should be applied to a tissue is limited by a dose which may be transmitted to healthy adjacent tissues. Moreover, some tissues and organs are more sensitive to radiation and chemical damage than others, and thus treatment of tissue adjacent to such tissues and organs can be severely limited.
Additional background art includes:    U.S. Pat. No. 6,852,095 to Ray;    Published U.S. Patent Application No. 2008/0033471 of Paz et al;    Published U.S. Patent Application No. 2008/111078 of Shohat;    PCT Published Patent Application WO/06001009 of Paz et al;    PCT Published Patent application WO/2008/111078 of Shohat; and    “The Seldinger technique”, a reprint from Acta Radiologica 1953; AJR Am J Roentgenol. 1984 January; 142(1):5-7.